Carving device

ABSTRACT

A modeling device intended for applying wax to the crown region of a tooth which is to be modeled is designed for the purpose of improving its characteristics in use such as its handling during modeling work, when inserting new wax cartridges etc. as an elongated, writing device-like base body, which comprises at one end a modeling tip ( 6 ) and inside accommodates a forward feed drive for a wax cartridge and a heating device which is used to render the wax to be processed into a liquid state at the end ( 5 ) facing the modeling tip ( 6 ), so that as the forward feed drive is actuated liquid wax can be discharged from the outlet ( 9 ). For the purpose of supplying electric energy a cable ( 2 ) is attached to the front side end ( 5 ) and in fact to the concave side of the curved modeling tip ( 6 ). The connection of the cable ( 2 ) prevents neither the manner in which the device is guided when moving nor the view of the actual working area. The forward feed drive consists of a motor which is connected to a piston by means of a threaded spindle, which is guided in a spindle nut fixedly held within the device, the said piston forming the force transmitting member to the wax cartridge. Both the piston and also the motor are held within the casing in an axially displaceble yet with respect to its longitudinal axis ( 16 ) non-rotatable manner. Overall, a device which meets all practical requirements of the modeling art is provided, which device is characterized by an increased level of comfort in comparison to comparable known devices.

[0001] The invention relates to a modeling device according to thepreamble of claim 1.

[0002] Such devices are known per se in connection with variousfunctions, in particular for various materials. One importantapplication area relates to prosthodontics, in particular theapplication of wax to the crown region of a tooth to be modeled. This[doctrine] is known on the one hand such that by means of a modeling tipwax is received in a flowable consistency, i.e. it can be modeled in aplastic manner, and transferred to the crown region, where it issubsequently worked. As the spatial structures to be worked arerelatively small, this activity requires that the wax to be applied ismetered in an extremely precise manner. Also, it is laborious andtime-consuming using a modeling tip for the flowable wax to be receivedand applied at a site which is remote from the processing location.

[0003] A modeling device is known from Dental-Labor XLVIII, [DentalLaboratory XLVIII] Issue April 2000, wherein a tank which receives a waxcartridge is provided within a modeling device and said tank can beheated electrically to the same extent as a modeling tip. A mechanicalpush button is used to meter the wax which issues out of the modelingtip and the modeling device is operatively connected to an energy supplyunit.

[0004] A device for wax modeling cast models in dentistry is known fromDE 94 12 336 U1, which device consists of an elongated, base body whichis a similar shape to a writing device and which serves as a storagechamber for the wax and whose funnel-shaped end region is provided withan outlet orifice and a coupling part, onto which coupling partconventional modeling tips can be placed. The wax storage chamber isencompassed by electrically heatable heating elements in the form of aheating mat which is connected to a thermostat, adjusting elements and adisplay device. Once the entire wax storage chamber has been heated, aheat insulation layer is provided between the casing of the base bodyand the heating mat. The end region, remote from the modeling tip, ofthe base body serves to insert wax cartridges known per se into the waxstorage chamber, wherein likewise a pneumatically operatedpiston-cylinder unit is inserted via this end region into the base bodyand forms a forward-feed drive. For control purposes, the device isprovided with sensor buttons which are located on the front side end ofthe base body facing the modeling tip. Depending upon the temperature ofthe melted wax inside the wax storage chamber, it can be difficult tometer in a precise manner the wax to be dispensed. It is a drawback asfar as the operating technology is concerned, that the end remote fromthe modeling tip is not only connected to lines for supplying compressedair but is also connected to lines for supply electrical energy. Thisnot only impairs the view of the immediate working region of themodeling tip but precise movements are also difficult. A furtherunfavorable condition is the complete encasement of the wax storagechamber in a heat-insulating material, as this inevitably leads to anincrease in the cross-sectional dimensions of the device.

[0005] A further comparable device is known from DE 33 46 254 A1, whichdevice consists of an elongated base body, wherein the wax cartridges tobe processed can be inserted either via the rear side end of the basebody or via the front side end thereof, in other words, in each casehaving first dismantled the function elements located on these two ends.However, as a departure from the subject matter of DE 94 12 336 U1, onlythe front side end is heated, i.e. the end facing the modeling tip, sothat there is no necessity to encase the wax storage chamber in aheat-insulating casing. The forward-feed drive used can comprise anelectromotor or also a piston cylinder unit requiring a supply ofcompressed air. However, a disadvantage of this known device is also thecondition that connection lines for supplying electrical energy andoptionally also for supplying the compressed air are located on therearside end, i.e. the end remote from the modeling tip. Finally, it iscomparatively complicated to use a wax cartridge which is to beprocessed.

[0006] It follows from this that the object of the invention is toprovide a modeling device in accordance with the generic type such thatin addition to facilitating the handling of the modeling device, themetering of the substance to be applied and the application procedure assuch are also facilitated. This object is achieved in the case of such adevice by virtue of the features of the characterizing part of claim 1.

[0007] In a manner known per se, a motorized forward-feed drive for thesubstance to be processed is located inside the modeling device and theintended purpose of the said drive is to move this substance forprocessing in the direction towards the modeling tip. Morever, such aheating device is provided, which is capable of heating the substancesubstantially only at the end of the device facing the modeling tip andin particular until it issues out of the outlet of the modeling tip. Inother words, it is not the intention to heat the substance completely torender it all into a liquid state, which in addition to otherdisadvantages would not only be associated with a certain expenditure oftime but would simultaneously also be associated with a correspondingexpenditure of energy. Thus, only that region of the substance is heatedwhich during the procedure of being applied to the crown region to bemodeled, namely when exiting out of the said outlet, is subjected toplastic deformation and accordingly must be sufficiently flowable.Finally, a switching device is provided, which is connected directly tothe modeling device and during the working procedure is subjected to theimmediate influence of the user of the modeling device. This switchingdevice serves to control both the forward feed drive and also theheating device. It is preferably provided that the forward feed rate canbe continuously regulated within a fixed feed rate range which istailored to suit the working process. The same applies for the heatingdevice. In particular, the heat which is to be imparted into thesubstance being processed can preferably be regulated likewise within afixed range. The user of the modeling device thus has the opportunity tocontrol both the forward feed and also the consistency of the substancebeing processed in a manner tailored to suit the working step and alsothe characteristics of the substance.

[0008] In accordance with the invention, the base body of the modelingdevice is provided with an orifice which is intended for introducing thesubstance which is a solid body in its initial state. This orifice canbe closed and any flap or closing mechanism which does not impair thehandling of the modeling device may be used for this purpose.

[0009] The essential components of the forward feed drive in accordancewith the invention are formed by an electromotor, a threaded spindle anda spindle nut, wherein for example the threaded spindle is mounted in anon-rotatable manner within the modeling device, so that a rotation ofthe spindle nut can generate a forward feed movement in the longitudinaldirection of the modeling device. The rotational speed of the motor andthe pitch of the threaded spindle are designed with respect to thecontrol range of the forward feed rate. A piston which is connected tothe threaded spindle serves to provide a large-surfaceforce-transmitting element which is directly connected to the substancewhich is to be processed. Both for reasons of weight and also to avoidthe view being impaired, the cable is preferably attached to the frontside end of the modeling device, i.e. the end of the modeling devicefacing the modeling tip, and extends—in the direction towards the frontside—at an acute angle with respect to the longitudinal axis of themodeling device. This embodiment also serves to simplify the practicalhandling and thus ensures a working result of high quality.

[0010] The features of claims 2 and 3 are directed at the detaileddesign of the heating device. According to this, the heating device canbe formed by a coil arrangement which serves to heat that part of thesubstance being processed which is facing the front side region, i.e.the region adjacent to the modeling tip. In a particularly advantageousmanner it is possible to provide several coils which are independent ofeach other and whose heating capacities can be controlled independentlyof each other. In this manner one coil can serve to provide basicheating and a further coil is designed merely for providing power peaks.The coils can be controlled, as far as their heating capacity isconcerned, independently of each other. However, it is also possible touse in place of the coil arrangements any other flat surface heatconductor structures which heat up as a result of a current passingthrough them and which are designed to transmit heat to the substancewhich is being processed.

[0011] According to the features of claim 4, the modeling tip comprisesan end section which is bent at an angle with respect to thelongitudinal axis of the modeling device. An alternative arrangementcould also be a corresponding curvature. This embodiment improves theline of view of the respective user to the site where the substance iscurrently being applied. The same applies for the site where a modelingprocedure is being performed using the modeling tip. This embodimentthus improves the working opportunities in the chewing surface depth.

[0012] The features of claims 5 and 6 are directed at the switchingdevice. According to this, the switching elements of said device areformed by sensors which render it possible to perform switchingprocedures without jarring so that neither the application procedure northe metering and modeling procedure are impaired by these switchingprocedures. The extent to which the heating and to the same extent theforward feed movement can be controlled is selected in dependence uponthe characteristics of the substance which is to be processed.

[0013] In accordance with the features of claim 8, the modeling tip ofthe modeling device can in addition be heated in a controlled manner. Inthis way, the forward feed and the procedure of metering the substancewhich is to be processed can be further improved.

[0014] Finally, according to the features of claim 9, the modelingdevice can be provided with an end switch which then triggers theautomatic return of the forward feed drive to its initial position whenthe substance which is to be processed has been dispensed from themodeling device.

[0015] The features of claim 10 are directed at a further designprinciple of the forward feed drive in accordance with the invention.According to this, a spindle nut is fixed, i.e. it is disposed withinthe elongated base body of the modeling device in such a manner as notto displace axially or rotate and a threaded spindle is provided whichat one end is connected to the piston which is intended for forwardfeeding the wax cartridge which is to be processed and at its oppositeend is connected to the motor. Both the piston and also the motor arearranged within the casing in a non-rotatable manner, so that arotational movement on the threaded spindle creates a correspondingaxial displacement of the entire assembly consisting of the threadedspindle, motor and piston. The spindle nut fixedly arranged within thecasing is located on the end of the casing remote from the modeling tip,in particular the said cut-out.

[0016] The features of claims 11 and 12 are directed at a first furtherembodiment of this design principle. According to this, the spindle nutcan be designed fundamentally merely in the shape of a half-shell, sothat a threaded engagement with the thread of the spindle shaft is onlyover a periphery of 180°. It has been established that such a limitedthreaded engagement can be regarded fundamentally as sufficient for thepurposes of the subject of the invention. Furthermore, the spindle nutcan also be formed as a longitudinally-divided body which consists oftwo half-shells which in their entirety can be completed to form a fullcylindrical shell. Both variants offer fundamentally simpleopportunities of releasing the threaded engagement between the spindlenut and the threaded spindle so that in the released state the entireassembly consisting of the piston, the threaded spindle and the motorcan be displaced manually within the casing. Such a utilization isavailable when the casing in accordance with the invention is providedwith a lateral cut-out through which the wax cartridge can be inserted.In this manner, the opportunity is available once the wax cartridge hasbeen consumed for the piston to be displaced by manual intervention viathe said cut-out back into its rearward position, i.e. the positionwhich is suitable for inserting a new wax cartridge.

[0017] The features of claims 13 and 14 are directed at a furtherembodiment of the principle of the longitudinally-divided spindle nut.According to this, the two half-shells of the spindle nut areaccommodated in a bearing ring of elastomer material inside the casingof the modeling device and moreover there are provided in adiametrically opposed position separating bodies which preferablycomprise a wedge shape and which can be pressed in radially with respectto the likewise longitudinally-divided bearing ring in the gap betweenthe two annular half-shells of the bearing ring, so that according tothis movement a force can be exerted on the half-shells of the spindlenut, which force separates the said half-shells perpendicularly to theirjoint face. As a result of being received in the elastomer bearing ring,such a movement is likewise possible as the bearing ring deforms in anelastic manner and for this purpose it is designed accordingly in itsdimensions and material. At the same time, in this manner the bearingring serves to provide the necessary restoring force or it at leastprovides a contribution thereto. Moreover, it is essential to theinvention that for the purpose of actuating the separating bodies analready existing sliding sleeve is involved. For example, the separatingbodies can protrude slightly out of the outer surface of the modelingdevice, so that as a result of their “extending” on the outerside theycan be pressed inwards radially by means of the sliding sleeve. Likewisein the embodiment of this principle it can be provided that the wedgesurfaces of the two separating bodies are connected to the bearing ring,for example adhered or vulcanized thereto and that as a result ofextending over the radial outer sections of the separating wedges thematerial is displaced in a radially inwards direction and the bearingring halves are removed from each other. When the bearing rings are in astate separated from each other in which the threaded engagement betweenthe threaded spindle and the spindle nut is released, the separatingbodies are thus elastically deformed, so that in turn restoring forcescan be derived from this deformation state, which forces are releasedonce the sliding sleeve has been removed and the bearing rings drawtogether, so that in turn a threaded engagement is produced between thespindle nut and the threaded spindle.

[0018] The last-mentioned principle is further explained in a precisemanner according to the features of claim 15, in that when thehalf-shells of the spindle nut are lying adjacent to each other theirposition is fixed in a form-locking manner relative to each other. Thiscan be effected, for example, by means of engaging arrangements whichare formed according to a type of tongue and groove connections, whereina guiding effect can be exerted simultaneously on the half-shells bymeans of a conical design of the tongue and groove connections.

[0019] The drive principle mentioned in the first instance, where thespindle nut is only formed by one half-shell can be achieved accordingto the features of claim 16, in that the half-shell forms the closure ofthe cut-out in the wall of the casing of the modeling device, whichcut-out is otherwise used to insert a wax cartridge. This means that theinnerside of the half-shell is integrally provided with a threadedprofile which extends over the peripheral angle of preferably 180°. Thisalso means that the threaded engagement between this spindle nut and thethreaded spindle can be released in an extraordinarily convenientmanner, in that the said cut-out is merely revealed by removing thehalf-shell.

[0020] According to the features of claims 17 and 18, the modelingdevice is provided with a display device by means of which the user ofthe device is made aware of the extent to which the wax cartridgeinserted has already been consumed, so that it might now be necessaryimminently to insert a new wax cartridge. This is achieved by virtue ofthe fact that the displaced position of the piston, of the motor or anyother function element which is connected to this assembly which can bedisplaced in the longitudinal direction of the device is visiblydisplayed towards the outerside of the device. By way of example only,this can be achieved by means of a signal body which is integrallyformed on the motor casing, wherein this signal body is accommodated ina sliding manner in an outer cut-out of the casing.

[0021] A spring according to the features of claim 19 provides theopportunity of holding the wax cartridge constantly in a definedposition relative to the piston within the casing of the device. Thus,the wax cartridge can be fed forward at any time in a manner free ofplay. This condition has a favorable effect with respect to metering ina precise manner the wax which is to be dispensed. As a result of thewax cartridge being in a defined position within the casing,reproducible heating conditions can be created to the same extent, acondition which is of importance for the rapid readiness for service ofthe modeling device.

[0022] Owing to the fact that it is not possible to exclude reliablyimpurities from the substance in the wax cartridge but also owing to theextraordinarily small dimension of the through-flow cross-section of themodeling tip, it is always to be expected that these cross-sections willbecome blocked. However, owing to these small dimensions cleaning tofree this cross-section of blockages is time-consuming. According to thefeatures of claims 20 and 21 a sieve or filter is provided for thispurpose which has a mesh or pore width which is designed with respect toretaining offending foreign bodies. This sieve is provided within thecasing in such a manner that it can be replaced, a characteristic whichcan be advantageously achieved by means of an insertion piece which isreleasably connected to the innerside structures of the device. Thisconnection can be by way of a screw connection, a bayonet closure or thelike. The sieve is thus changed merely by handling the substantiallylarger insertion piece.

[0023] The quantity of liquid substance issuing from the modeling tipshould be tailored as precisely as possible to suit the actualrequirements with respect to working accuracy. However, owing to theliquid wax portions located within the modeling tip and within the partchambers adjacent thereto within the casing of the modeling device,switching off the forward feed is associated with an unavoidableafter-flow of wax and in fact in dependence on the consistency of thetemperature of the wax and the pressure conditions prevailing in thesaid part chambers. In order to prevent this problem, a switching valveis provided in accordance with the features of claim 22, which switchingvalve is located in an expedient manner at the outlet of the casing andin fact immediately up stream of the entry cross-section of the modelingtip. In preference, an electromagnetic switching valve is used for thispurpose, which valve is controlled by the user by means of a sensorwhich is attached to the front side, i.e. to the side facing themodeling tip. When this valve is closed, any further liquid wax portionsare prevented from flowing out of the through-flow channel of themodeling tip owing to the vacuum created as a result of closing thevalve and owing to the capillary effect also exerted owing to the smallcross-section dimensions. It is possible to trigger a closure of thisvalve automatically and this closure can be associated, as far asswitching is concerned, with a termination of the forward feed.

[0024] A consequence of switching off the forward feed movement isinitially characterized by the pressure conditions being maintainedwithin the device, which results—as mentioned above—in a tendency forfurther substance to flow out of the modeling tip. This tendency is atleast greatly reduced by virtue of the fact that according to thefeatures of claim 23, the energy supply unit which also serves tocontrol the forward feed is designed with the stipulation that once theforward feed procedure is completed, the piston is drawn back by adefined linear element, i.e. in the direction away from the modelingtip. This feature thus serves the comfort factor during the practicalhandling of the device and can likewise be automatically triggeredaccording to predeterminable linear elements. The linear elements are tobe selected such that the spring mentioned in the introduction maintainsits influence regardless of the piston having been drawn back.

[0025] According to the features of claim 24, the energy supplycomprises an electric battery or can comprise an accumulator. The devicein accordance with the invention can thus be operated independently fromthe mains.

[0026] The features of claims 25 and 26 are directed at furtheradvantageous embodiments of the device. Accordingly, the modeling tip isconnected to the modeling device in such a manner that it can bereplaced, so that if necessary in dependence upon the modelingprocedures to be performed different modeling tips can be used. Atriangular cross-sectional design of the elongated modeling device whichin principle is similar to a writing device serves to improve thehandling comfort. The main area of application of the modeling device isthe working procedure of applying wax in prosthodontics. The abovedescribed design principle can, however, be used in numerous otherapplications, where masses which are solid in their initial state, forexample synthetic material, are applied in metered quantities toworkpieces and must be modeled in a still flowing state. Finally onepossible fundamental application is also during soldering procedures.

[0027] The invention is described in detail herein under with referenceto the exemplified embodiments illustrated schematically in thedrawings, in which:

[0028]FIG. 1 shows a view of the modeling device in accordance with theinvention;

[0029]FIG. 2 shows an enlarged partial illustration of an axialcross-section of a region II of the modeling device in accordance withthe invention;

[0030]FIG. 3 shows an enlarged partial illustration of an axialcross-section of the tip of the modeling device in accordance with theinvention;

[0031]FIG. 4 shows a partial illustration of an axial cross-section ofthe end facing the tip of the modeling device;

[0032]FIG. 5 shows an illustration similar to that shown in FIG. 4 ofanother embodiment of the modeling device;

[0033]FIG. 6 shows a partial illustration of an axial cross-section ofthe end of a modeling device remote from the tip;

[0034]FIG. 7 shows a partial illustration of a lateral view of a detailVII of FIG. 6;

[0035]FIG. 8 shows an end view of the component illustrated in FIG. 7according to the line of view VIII;

[0036]FIG. 9 shows a cross-sectional illustration of a furtherembodiment of a device in accordance with the invention according to thecutting plane IX-IX of FIG. 10;

[0037]FIG. 10 shows a lateral view in a partial cross-sectionalillustration of the device in accordance with the invention illustratedin FIG. 9.

[0038] The modeling device in accordance with the invention illustratedin FIGS. 1 to 3 consists generally of a modeling device 1 which is to beguided manually and which is connected via a cable 2 to an energy supplyunit 3. The energy supply unit 3 is designed for connection to aconventional electric mains and for providing an output voltage and anoutput current which are dimensioned and can in particular be regulatedin dependence upon the electrical functions of the modeling deice 1. Theenergy supply unit can thus generally also be designed for controlpurposes.

[0039] The modeling device 1 consists of a tubular base body, whoseregion facing an end 4 is intended and designed inter alia for thepurpose of receiving a forward feed drive and whose end 5 lying oppositethereto is intended and designed for the purpose of receiving in aninterchangeable manner a modeling tip 6.

[0040] The part of the base body facing the modeling tip 6 is designedas a hollow chamber which is intended to receive a rod-shaped wax body7. It is essential that the part of the hollow chamber facing the end 5and in particular the modeling tip 6 are capable of being heatedelectrically and this is achieved by virtue of the fact that these partsare disposed in an electrically insulated manner with respect to theother sections of the base body and are designed as parts of an electricconductor which can thus be heated according to the voltage influence.The said hollow chamber is also connected to allow through-flow to thecentral channel 8 of the modeling tip 6, whose outlet is open.

[0041] The said wax cartridge 7 is moreover dimensioned such that thecross-section of the hollow chamber is filled and this wax cartridge 7lies on its end remote from the modeling tip 6 on a piston 10 which isreceived in a slidable manner within the base body of the modelingdevice 1 in the direction of the arrow 11.

[0042] The numeral 12 designates a threaded spindle, one end of which isconnected to the piston 10, which is received in a non-rotatable mannerwithin the base body, and the other end of which is received in aspindle nut [in a manner not illustrated in the drawing] which canrotate by means of an electromotor which is disposed within the basebody and is likewise not illustrated in the drawing. A rotation of thespindle nut is thus converted accordingly into an axial movement of thepiston 10 in the direction of the arrow 1.

[0043] The said base body is provided on its region facing the end 5with a cut-out, which is approximately the length of a sliding sleeve 13which can be displaced along the base body for the purpose of revealingor closing this cut-out. This cut-out is dimensioned such that a waxcartridge 7 can be inserted into the said hollow chamber of the basebody.

[0044] The modeling tip 6 consists of a first part which extends in theaxial direction of the base body and a part which is bent at an anglewith respect thereto in an inclined manner in relation to the axisthereof and terminates in the outlet 9.

[0045] Two sensor switches [not illustrated in the drawing] serve on theone hand to control the motor allocated to the piston 10 and on theother hand to control the heating energy which is to be transmitted tothe end region of the wax cartridge and or the wax located within thechannel 8. In a particularly advantageous manner, the channel 8 cancomprise a cross-section which widens as it progresses in the directiontowards the outlet 9.

[0046] Basic heating is provided, in particular regulated, regularly viathe energy supply unit 3, so that only power peaks are controlled viathe corresponding sensor switch on the modeling deice 1 for the heatingrequirements. These power peaks can preferably be utilized for heatingthe metallic modeling tip 6.

[0047] The cable 2 is attached in accordance with the invention to thefront side end 5 of the base body, i.e. the end 5 of the base bodyfacing the modeling tip. In reality, the connection point of the cable 2can be disposed approximately in the region of the front third of thelongitudinal extension of the base body. For this purpose, the base bodyis provided with a connection point 15 by means of which the cable 2 isrouted out of the base body at a right angle with respect to thelongitudinal axis 16. It is also possible to have an obtuse angle, sothat the cable 2 is routed towards the rearward end of the base body,i.e. the end remote from the modeling tip.

[0048] In a particularly advantageous manner, the connection point 15can be provided directly on the front-side end of the base body. In thiscase, the application and the function of a sliding sleeve 13 (FIG. 1)is not impaired.

[0049] As illustrated in FIG. 1, the modeling tip is formed curved withrespect to the longitudinal axis 16 of the modeling device 1 and extendsat an obtuse angle with respect to this longitudinal axis. For reasonsrelating to the operating technology, the connection point 15 for thecable 2 is located on the concave curved side of the modeling tip 6, sothat when working with the device the cable exits towards the lower sideand does not impair the handling opportunities of the device.

[0050] In place of a sliding sleeve 13 it is possible in this case,insofar as the spacial positioning of the connection point 15 makes thisnecessary, to provide another flap or sliding element by means of whicha cut-out in the base body can be revealed or closed, which serves forthe insertion of wax cartridges into the modeling device 1.

[0051] The main application area of the modeling device 1 in accordancewith the invention is the application of wax for example to the crownregion of the tooth base body of a prosthesis and for this purpose a waxbody 7 is inserted into the modeling device 1. Then, electrical energyis supplied to the modeling device 1 by means of the energy supply unit3 via the cable 2 in a quantity such that on the one hand by actuatingthe respective sensor switch the said motor can be activated and as aconsequence the wax body 7 is displaced in the direction towards the end5 of the base body. Likewise by actuating another sensor button the endregion of the wax substance can be electrically heated, so thatdepending upon the supply movement generated via the piston 10 liquidwax exits from the outlet 9 of the modeling tip 6 and by means thereofis applied to the tooth base body where it is subsequently modeled. Itis essential in this connection, that the motor is designed inconnection with the said threaded spindle 12 with regard to itselectrical parameters such that it is possible to regulate preferably ina continuous manner the rotational speed and thus the forward feedwithin a control range.

[0052] The control unit allocated to the motor can be designed in anadvantageous manner such that the piston 10 is automatically moved toits rearward position, i.e. the position lying at the end of the basebody remote from the modeling tip 6, as soon as an obstacle, jamming orthe like occurs during the forward feed of the wax body 7. Thisproblematic state can be signaled optically and acoustically.

[0053] Moreover, the electrical concept of the heating arrangement canbe designed in such a manner that even without actuating the sensor,pre-heating occurs, however, this does not lead to wax issuing out ofthe outlet 9. On the other hand, as a consequence of actuating thesensor more comprehensive heating can be achieved, particularly in theregion of the modeling tip, and thus liquid wax issues out of the saidoutlet. Moreover, the heating of the wax substance controlled in thisway by means of a sensor can be designed advantageously such that thequantity of heat being introduced can be controlled within a controlrange, so that in the region of the outlet 9 wax is available in aquantity and in a consistency necessary for the modeling procedure. Theenergy supply unit 3 can be used to regulate a basic heat requirement.

[0054] Irrespective of the connection site of the cable 2 to the basebody of the modeling device 2, grooves can be provided on the innersideof the base body for the purpose of receiving electric lines, by meansof which on the one hand the said motor and on the other hand theheating device located on the end 5 of the base body can be suppliedwith electrical energy.

[0055] However, the cable 2 attached to the connection point 15 can alsoextend at an optional angle with respect to the longitudinal axis of themodeling device 1 or can be attached thereto.

[0056] Referring to FIGS. 4 to 10, further exemplified embodiments ofthe modeling device in accordance with the invention will be describedherein under and again function elements which correspond to those ofFIGS. 1 to 3 will be designated with like numerals, so that it will notbe necessary to repeat a description thereof.

[0057] An essential feature of the exemplified embodiment illustrated inFIG. 4 of a modeling device 18 is an insertion piece 19 which is screwedinto a corresponding threaded bore of the casing of the modeling device18 by way of a front-side threaded section 20 which is disposed facingthe end 5. The threaded section 20 comprises a smaller diameter than theadjacent thereto, remaining base body of the insertion piece 10 andencompasses a cylindrical hollow space 21 which extends coaxially withrespect to the longitudinal axis 16 of the modeling device 18. Bores22,23 likewise extend in a coaxial manner with respect to thislongitudinal axis 16 and by means of these said bores the hollow chamber21 [is connected] on the one hand to the chamber intended for receivingthe wax body 7 and on the other hand to the channel 8 of the modelingtip 6. The insertion piece 19 encompasses on its end remote from thethreaded section 20 for its part a hollow chamber 24 which generallyextends in a conical manner in the direction towards the wax cartridge7.

[0058] A fine mesh sieve 25 is disposed [not illustrated in detail inthe drawing] within the hollow chamber 21 and must be attached in such amanner that the liquid wax flowing through this hollow chamber 21 cannotcause the position of the said sieve to change.

[0059] The likewise-mentioned further hollow chamber 24 of the insertionpiece 19 serves to receive a spring 26, one end of which rests againstthe facing surface sections of the hollow chamber 24 and the oppositeend of which rests against the facing end side of the wax body 7.

[0060] The spring 26 acts in such a manner that the wax body 7 is inconstant contact with the piston 10 (FIG. 2) and thus has a definedstarting position. In order to avoid an excessive quantity of heat beingtransmitted to the wax body 7 by way of the generally metal spring, itis possible to dispose at the point of contact between the spring 26 andthe wax body 7 an insulating element [not illustrated in the drawing]which consists of a material which has a lower caloric conductibility

[0061] Illustrated in the drawing in FIG. 4 is a cut-out 27 which can berevealed or closed by means of displacing the sliding sleeve 13 in thedirection of the arrow 11, for example, for the purpose of inserting anew wax body 7 into the modeling device 18 once a wax body has beenconsumed.

[0062] The exemplified embodiment illustrated in FIG. 5 of a modelingdevice differs from the one shown in FIG. 5 merely by the fact that asieve 25 is now received within the hollow chamber 24 of the insertionpiece 19.

[0063] The arrangement of a sieve 25 on the output side with respect tothe modeling device increases the operating reliability as the finestimpurities in the substance of the wax body are practically unavoidableand these impurities can create problems, particularly in the region ofthe channel 8 of the modeling tip 6, which regularly prevent thethrough-flow of the liquid wax. The work involved in cleaning themodeling tip 6 is relatively troublesome and time-consuming owing to theextremely small diameter of . . . mm of the tip, so that the arrangementof a sieve can remedy this.

[0064] FIGS. 7 to 9 illustrate an exemplified embodiment of the driveconcept of a modeling device 28 in accordance with the invention. Thenumeral 29 designates a half-shell which is inserted into acorresponding cut-out of the casing of the modeling device 28 and islatched preferably in an elastic manner in the inserted position. Amagnetic securing arrangement is also possible. However, relevantlatching means are not illustrated in the drawing. The half-shell 29closes the cut-out which is intended for the insertion of the wax bodiesand the half-shell 29 in the inserted state forms a component of thecasing wall of the modeling device 28, which is encompassed by thesliding sleeve 13.

[0065] The half-shell 29 is provided at one of its ends in one piecewith a threaded section 30 which is intended for engagement with thethread of the threaded spindle 12. The half-shell 29 is thus held in theinstalled state in a non-rotatable manner relative to the longitudinalaxis 16 of the modeling device 28. The threaded section 30 extendsstarting from the one end of the half-shell 29 over only a partiallength thereof, whereas the half-shell also follows on the innerside theperipheral region of the casing of the modeling device 28 and is thusdesigned for the purpose of guiding the piston 10. It is essential thatthe piston 10 is guided, within the chamber formed in this way, likewisein a non-rotatable manner with respect to the longitudinal axis 16.

[0066] In the illustration as shown in FIG. 6, the half-shell 29 issecured in a form-locking manner as a result of the sliding sleeve 13being pushed over in its assembly position. This is only to beunderstood as an example. Thus, a possible security component is asleeve which can rotate on the base body around the axis thereof andwhich is provided with a cut-out for the purpose of removing thehalf-shell, so that depending upon the rotational angle position of thissleeve, the half-shell is again secured in a form-locking manner.

[0067] The threaded spindle 12 is drivingly connected at its end remotefrom the piston 10 to a motor 31, in this case an electromotor which islikewise guided within the casing of the modeling device 28 in such amanner as to be non-rotatable about the longitudinal axis 16. It isevident that in the case of this constellation depending upon thedirection of rotation transmitted via the motor 31 to the threadedspindle 12 the entire assembly, consisting of the motor 31, the threadedspindle 12 and the piston 10, can be moved in a straight line in thedirection of the arrow 11.

[0068] The drawing in FIG. 6 illustrates the piston 10 in its oneboundary position, in which after the sliding sleeve 13 has beendisplaced accordingly and the half-shell 29 removed a new wax body canbe inserted into the modeling device. In this connection, theillustrated device still offers the advantage that after dismantling thehalf-shell 29 the piston 10 can be displaced in the most convenientmanner manually into its rearward boundary position illustrated in FIG.6.

[0069] Moreover, the illustrated function principle can be modified inmany ways. Accordingly, a further half-shell-like threaded section canlie opposite the half-shell 29, in particular its threaded section 30,which half-shell-like threaded section is disposed likewise in anon-rotatable manner relative to the longitudinal axis 16, so that thethreaded spindle 12 is guided through a complete non-rotatably disposedthreaded profile. However, in this case the advantage of the convenientmanual sliding back of the piston 10 no longer exists after a wax bodyhas been consumed.

[0070] In addition, whilst maintaining the drive concept, a threadedprofile 30 can be disposed moreover also in an axially fixed andnon-rotatable manner at a different site of the inner chamber of thecasing of the modeling device 28.

[0071] The numeral 32 designates an elongated orifice in the wall of themodeling device 28 which is closed on the outer side by means of atransparent cover 33. The cover 33 terminates flush with the outersurface of the modeling device 28 and comprises a thickness which issubstantially less than the thickness of the wall of the device casing.A, for example, cuboid-shaped signal body 34 is accommodated within theremaining thickness region of the orifice 32 and this signal body is infixed connection with the motor 31. The signal body 34 comprises in anexpedient manner a particular coloring so that its position can beeasily recognized along the orifice 32.

[0072] The orifice 32 is preferably designed according to such alongitudinal extension which corresponds in general to the displacementfeature of the motor 31, so that it is possible using the position ofthe signal body 34 to recognize the extent to which the wax bodyinserted in the modeling device has already been consumed. If necessary,it is also possible in this case to provide a scale on the outer side ofthe device, which displays the residual content of wax which is capableof being processed.

[0073]FIGS. 9 and 10 illustrate a further possible embodiment of thedrive concept of the invention. The threaded spindle 12 in this caseengages with a longitudinally-divided spindle nut which thus consists oftwo half-shells 36, 37 and is disposed, whilst providing an intermediatearrangement of a bearing ring 38 which consists of an elastic material,for example an elastomeric material, in the modeling device 35 axiallyin a non-displaceable manner and with respect to the longitudinal axis16 in a non-rotatable manner. For example, the bearing ring 38 canconsist of rubber which is adhered on the one side to the facingsurfaces of the modeling device 35 and on the other side to thehalf-shells 36, 37. For the purpose of ensuring a clear assemblyposition of the two half-shells 36, 37, the said half-shells engage intheir joint face in a form-locking manner. For this purpose, twostrip-like projections 39 are formed as one on the half shell 36 and infact protruding out of the joint face and these projections are insertedin corresponding opposite grooves of the half-shell 37 and the positionof the two half-shells is stabilized relative to each other.

[0074] The bearing ring 38 is divided longitudinally and separatingbodies 40, which are wedge-shaped in a mutually diametrically oppositemanner and are dimensioned and created in the same manner with respectto each other, protrude into the gap, which extends in the direction ofthe longitudinal axis 16, between the two half-shells of the bearingring 38. Moreover, these separating bodies penetrate cut-outs in thecasing of the modeling device which extend in the longitudinal directionof the modeling device 35 and can in addition, as illustrated in FIG.10, comprise in the longitudinal direction 16 on both sides with respectto a middle plane a ramp-like downward inclining section, i.e. sectionwhich protrudes on the outer surface of the casing wall of the modelingdevice 35. In addition, the separating bodies 40 are designed with thestipulation that as a result of the sliding sleeve 13 being pushed overthey are displaced radially inwards with respect to the modeling device35 and as a result of their wedge-shaped design they exert separatingforces in the direction of the arrows 41 onto the two half-shells 36,37. Furthermore, the separating bodies 40 are dimensioned and designedto such an extent that by way of these separating forces, thehalf-shells 36, 37 under elastic compression of the half-shells, whichcooperate therewith, of the bearing ring 38 are removed so far away fromeach other that a threaded engagement between the inner thread of thehalf-shells 36, 37 and the threaded spindle 12 is released. This stateis achieved if the sliding sleeve 13 has reached the summit point 42 ofthe separating bodies 40, so that as a consequence of the piston 10(FIG. 2) and therewith the entire assembly consisting of the threadedspindle 12 and the motor attached thereto can be manually displaced backinto its rearward position.

[0075] Further numerous modifications of the subject of the applicationare possible. Accordingly an energy supply unit 3 which cooperates withthe motor 31 can be designed to the extent that after the motor hascompleted the forward feed, i.e. after a force is exerted on the waxbody 7 which displaces said wax body in the direction towards the end 5,automatically a rearward movement of the piston 10 away from the end 5by a selectable path element is initiated. This feature can contributeto preventing further liquid wax from flowing out of the modeling tip 6.

[0076] Moreover, the modeling device can be provided on its end 5 with apreferably electromagnetically actuated valve, by means of which theflow of wax into the modeling tip can be released or blocked. Also inthis manner, further wax can be prevented from flowing, wherein it isassumed that in the case of the extremely small cross-sectionaldimensions of the channel 8 within the modeling tip 6 the wax present inthis channel is also held back as a result of the capillary effectexerted thereon.

[0077] Thus, numerous measures are undertaken which render it possibleto work with the modeling device in an extremely comfortable manner andto meter in an extremely precise manner the quantity of liquid wax whichissues out of the outlet of the modeling tip 6.

1. Modeling device for manually applying and modeling substances, namelywax, which are flowable when subjected to heat, consisting of a modelingdevice (1, 18,28, 35) and an energy supply unit (3) which are mutuallyconnected via a cable (2), wherein the energy supply unit (3) isdesigned for providing and transmitting electrical energy to themodeling device with the stipulation that the substance can be convertedinto a flowable state and can be dispensed via the outlet (9), of amodeling tip (6), having a motorized forward feed drive intended forconveying the substance to be processed in the direction of the end (5),facing the modeling tip (6), of the base body of the modeling device,having a heating device which is intended and designed for the purposeof converting the substance only at the end (5) of the base body into aflowable state, so that in connection with the movement of the substancecreated by the forward feed drive, the said substance can be dischargedfrom the outlet (9), and having a switching device for controlling theforward feed drive and the heating device, wherein the substance is asolid body in the initial state, namely in the form of a wax cartridge(7), which can be inserted into the base body and in this is operativelyconnected to the forward feed drive and wherein the forward feed drivecomprises an electromotor, characterized in that the base body isprovided on its region facing the end (5) with a cut-out (27) which isintended for inserting the wax cartridge (7) and which can be closed,that moreover the forward feed drive in addition to a piston (10)comprises a spindle nut and a threaded spindle (12) which is connecteddirectly to the piston (10), wherein the piston (10) forms theforce-transmitting member between the threaded spindle (12) and thesubstance to be processed and that the cable (2) is attached to thefront region of the base body of the modeling device, i.e. to the regionfacing the modeling tip.
 2. Modeling device as claimed in claim 1,characterized in that the heating device is formed by a coil arrangementby means of which the said substance can be heated with a view toconverting it into a flowable state.
 3. Modeling device as claimed inclaim 2, characterized by several coil arrangements which can becontrolled separately from each other and which can be characterized bydifferent heating capacities.
 4. Modeling device as claimed in any ofthe preceding claims 1 to 3, characterized in that the modeling tip (6)comprises an end section which extends at an angle with respect to thelongitudinal axis of the base body.
 5. Modeling device as claimed in anyof the preceding claims 1 to 4, characterized in that the switchingdevice consists of sensors which are intended and switched for thepurpose of controlling the forward feed and the heating processes. 6.Modeling device as claimed in any of the preceding claims 1 to 5,characterized in that the heating process can be controlled.
 7. Modelingdevice as claimed in any of the preceding claims 1 to 6, characterizedin that the forward feed movement can be controlled.
 8. Modeling deviceas claimed in any of the preceding claims 1 to 7, characterized in thatthe heating device can also be designed for heating the modeling tip (6)in a controlled manner.
 9. Modeling device as claimed in any of thepreceding claims 1 to 8, characterized by an end switch which causes theforward feed drive to return to an initial position.
 10. Modeling deviceas claimed in any of the preceding claims 1 to 9, characterized in thatthe spindle nut of the forward feed drive is disposed in anon-displaceable and non-rotatable manner within the casing of themodeling device (1, 18, 28, 35) and that the motor (31) of the forwardfeed drive is held in a displaceable but non-rotatable manner within thecasing.
 11. Modeling device as claimed in claim 10, characterized inthat the spindle nut is formed by a half-shell (29) which is releasablyconnected to the casing of the modeling device.
 12. Modeling device asclaimed in claim 10, characterized in that the spindle nut is formed bytwo half-shells (36, 37) which when complete form a full cylindricalshell and which can be moved within the casing of the modeling device ina first position characterized by an engagement with the thread of thethreaded spindle (12) and in a second position in which this threadedengagement is released.
 13. Modeling device as claimed in claim 12,characterized by separating bodies (40) which are intended and designedfor cooperating with a sliding sleeve (13) and by means of which a forcecan be exerted on the half-shells (36,37) perpendicular to the jointface between the half-shells (36,37).
 14. Modeling device as claimed inclaim 11 or 12, characterized in that the two half-shells (36,37) aredisposed in a bearing ring (38) which consists of an elastomericmaterial and which is attached to the innerside of the casing of themodeling device (35).
 15. Modeling device as claimed in any of thepreceding claims 12 to 14, characterized in that the two half-shells(36,37) in their position lying against each other along a joint faceare secured in a form-locking manner at least in the joint face and in adirection perpendicular to the longitudinal axis (16) of the modelingdevice.
 16. Modeling device as claimed in claim 11, characterized inthat the one half-shell (29) is intended and designed for closing thecut-out (27) and comprises on its innerside a threaded section (30), thethread of which is intended for cooperating with the threaded spindle(12).
 17. Modeling device as claimed in any of the preceding claims 1 to16, characterized by a display device which is intended and designed fordisplaying the movement, in particular the position of the piston (10)or of the motor (31) within the casing of the modeling device (1, 18,28, 35).
 18. Modeling device as claimed in claim 17, characterized inthat a signal body (34) which is guided in an orifice (32) of the saidcasing is formed as one on the motor (31).
 19. Modeling device asclaimed in any of the preceding claims 1 to 18, characterized in thatthe wax cartridge (7) rests at its end facing the modeling tip (6) atthe end side on a spring (26).
 20. Modeling device as claimed in any oneof the preceding claims 1 to 19, characterized by a sieve (25) which islocated in the flow path of the liquid wax.
 21. Modeling device asclaimed in claim 20, characterized by an insertion piece (19) which isdesigned as a carrier of the sieve (25) and can be screwed in orinserted into the end (5) of the casing of the modeling device (14,18,28,35).
 22. Modeling device as claimed in any of the preceding claims1 to 21, characterized by a switchable valve which is disposed in aregion at least adjacent to the connection point of the modeling tip (6)and is designed for blocking or releasing a flow consisting of liquidwax.
 23. Modeling device as claimed in any of the preceding claims 1 to22, characterized in that the control, effected via the energy supplyunit (3), of the forward feed movement of the piston (10) is designedwith the stipulation that after the forward feed movement is completedthe piston (10) is automatically moved by a selectable path elementrearwards, i.e. in the direction away from the modeling tip (6). 24.Modeling device according to any of the preceding claims 1 to 23,characterized in that the energy supply unit (3) comprises an energyreservoir in the form of an electric battery.
 25. Modeling deviceaccording to any of the preceding claims 1 to 24, characterized in thatthe modeling tip (6) is connected to the modeling device (1, 18, 28, 35)in such a manner that it can be replaced.
 26. Modeling device accordingto any of the preceding claims 1 to 25, characterized in that theelongated base body of the modeling device (1, 18, 28, 35) comprises aform which has a generally triangular cross-section.